A138579 Numbers n such that 2^(2*n-9)-9 is prime.

5, 7, 9, 10, 13, 15, 21, 67, 75, 126, 130, 147, 165, 273, 286, 354, 369

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Example

2^(2*7-9)-9=23, 2^(2*9-9)-9=503, 2^(2*10-9)-9=2039, 2^(2*13-9)-9=131063

Mathematica

q=9; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 10^2}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]

Prog

(PARI) is(n)=isprime(2^(2*n-9)-9) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A114255 A350496 A358314 * A189703 A158251 A212191

Adjacent sequences: A138576 A138577 A138578 * A138580 A138581 A138582

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, May 13 2008

Status

approved